The subject matter disclosed herein generally relates to electromechanical thrust vector control actuators and, more particularly, to magneto-rheologic dampers for electromechanical thrust vector control actuators.
Rockets may be used to launch payloads into space, including inserting payloads into various orbits around the earth or other celestial bodies and/or directing payloads through space. Rockets are maneuvered by vectoring a rocket engine thrust direction. In some configurations, a thrust vector control system may be configured to use hydraulic rams to displace an engine nozzle angle relative to a rocket core axis to control a thrust vector to ensure proper propulsion of a rocket. Hydraulic rams require high pressure hydraulic fluid pumping systems capable of providing, for example, up to 4000 psia at flow rates of 40-100 gallons per minute or greater.
During a start cycle of a rocket engine, a large transient force can be applied to the thrust vector control actuators. This transient force can be several times larger than the normal maximum force applied to the thrust vector control actuator during normal operation. With this type of loading, hydraulic actuators are well suited, as they incorporate hydraulic high pressure relief valves which allow the actuator to momentarily drift, relieving the load, during the high load, short duration transient events. This type of response is acceptable during engine start, because the rocket has not left the launch pad yet and there is time to reposition the engine after the transient event has passed and the loads have returned to normal.
Electromechanical actuation systems may provide increased efficiency as compared to hydraulic actuators and provide additional safety benefits. However, small, high power density, electromechanical actuators may not be able to relieve high transient loads because of the rotational inertia associated with associated high speed electric motors. Accordingly, electromechanical actuators must be designed to mechanically support the high transient loads without experiencing damage. Accordingly, an electromechanical actuator capable of relieving short transient forces may provide benefits to rocket engines.